1. Field of the Invention
The invention relates generally to systems and methods used to decontaminate process streams that contain at least one contaminant. In particular aspects, the invention relates to systems and methods for decontaminating natural gas, liquid petroleum products or water in pipelines or production streams and for monitoring and control of the decontamination process.
2. Background of the Invention
Regulations require companies that produce or supply natural gas, crude oil, liquid petroleum gas or water to monitor product contaminants, mitigate potential hazards and maintain quality specifications. Typical contaminants include hydrogen sulfide (H2S), carbon dioxide (CO2), oxygen (O2), and biological populations. These contaminants can cause pipeline corrosion and subsequent rupture, narrowing of the line due to deposits, plugging, precipitation of solids, etc. Hydrogen sulfide, for example, is a highly corrosive and deadly substance that occurs naturally in a large number of hydrocarbon formations in south Texas and around the world. Hydrogen sulfide is not only harmful to humans, but when left untreated, can quickly corrode pipelines, potentially leading to ruptures and explosions. The U.S. Department of Transportation mandates that certain pipelines contain no more than 4 ppm of hydrogen sulfide at any given time. This is an extremely low concentration and can be difficult to measure accurately.
Conventional methods for treatment of contaminants have drawbacks. Depending upon the nature of the contaminant, a chemical scavenger or curative is typically added to the process stream. Inaccuracies in measurement of the contaminant frequently lead to overuse of injected curative. Operators routinely overcompensate when attempting to mitigate a risk by injecting excess chemical into the process stream. Because chemicals can be expensive, overuse translates into significant financial waste. Additionally, high levels of excess chemical can accumulate and must be removed or can build up on the pipeline wall, creating a rock-hard scale. Under certain conditions, rock hard scale builds up and can restrict the flow of gas causing further negative effects. If too much scale accumulates, the pipeline will require treatment with other potentially hazardous and expensive chemicals resulting in further health and safety risks and monetary loss.